Method for inhibiting differentiation and formation of coniferophyta male flower by treatment with prohexadione compounds

ABSTRACT

The present invention provides a method and composition for inhibiting the formation of Coniferophyta pollen, which has an excellent effect of inhibiting the formation of male Coniferophyta flowers without substantially inhibiting the elongation growth of the Coniferophyta trees. Prohexadione compounds are used as the active ingredients. The prohexadione compounds are, for example, as follows: formula (I).

TECHNICAL FIELD OF THE INVENTION

The present invention relates to a method and composition for inhibitingthe formation of Coniferophyta pollen, comprising the use of aprohexadione compound as an active ingredient. In particular, thepresent invention relates to a method and composition for inhibiting theformation of Coniferophyta pollen, such as Cryptomeria japonica (sugi)pollen, employing a composition that contains as a main ingredient, aprohexadione compound which does not substantially inhibit theelongation growth of Coniferophyta such as Cryptomeria japonica and hasan excellent effect of inhibiting the formation of male flowers thereof.

PRIOR ART TECHNOLOGY

Recently, Cryptomeria japonica pollinosis is one of typical allergicdiseases in early spring, in particular, March and April in Japan. It issaid that ⅕ of Japanese population are patients suffering fromCryptomeria japonica pollinosis. Under these conditions, measures forpreventing and inhibiting Cryptomeria japonica pollinosis are demanded.Although various investigations were recently made on the prevention andtreatment of Cryptomeria japonica pollinosis from the medicalstandpoint, any effective method for the prevention or treatment has notyet been established.

On the other hand, for preventing and inhibiting Cryptomeria japonicapollinosis, it is considered that botanical methods must be alsodiscussed. Namely, if the formation of the Cryptomeria japonica pollenper se can be prevented or inhibited, the cause of Cryptomeria japonicapollinosis is removed and Cryptomeria japonica pollinosis is effectivelyprevented. In this case, it is considered that the formation of maleflowers of Cryptomeria japonica which are the cause of the formation ofCryptomeria japonica pollen is to be inhibited.

After intensive investigations on substances inhibiting the formation ofmale flowers of Cryptomeria japonica, it has been found that theprohexadione compounds effectively control the formation of male flowersof Coniferophyta such as Cryptomeria japonica without substantiallyinhibiting the elongation growth of such Coniferophyta and has anexcellent effect of inhibiting the formation of male flowers thereof.

SUMMARY OF THE INVENTION

After intensive investigations made for the purpose of providing anagent for inhibiting the formation of Cryptomeria japonica pollen, whichdoes not substantially inhibit the elongation growth of Cryptomeriajaponica and has an excellent effect of inhibiting the formation of maleflowers thereof, it has been found that prohexadione compounds have suchan effect. The present invention has been completed on the basis of thisfinding.

DESCRIPTION OF EMBODIMENTS

The detailed description on the present invention will be made below.

The prohexadione compounds of the present invention inhibit thebiosynthesis of gibberellin. In particular, the prohexadione compoundsof the present invention inhibit the activity of 3-β hydroxynase whichis an enzyme involved in the hydroxylation at 3-β position in thebiosynthesis of physiologically active gibberellin. Various prohexadionecompounds are usable so far as they have such a function.

In addition, prohexadione compounds are rapidly decomposed and theyscarcely exert an influence on the growth of plants other thanCryptomeria japonica. Thus, the prohexadione compounds are suitable forthe environmental protection and safety of the plants.

The following examples of the prohexadione compounds of the presentinvention can be given: They are described in, for example, thespecification of JP Kokai No. Sho 59-231045. However, although thisspecification discloses that those compounds have selectivegrowth-inhibiting effect on plants such as rice plants and alsoselective herbicidal effect, it does not disclose or suggest the use ofthe compounds as agents for inhibiting the formation of Cryptomeriajaponica pollen, which do not inhibit the elongation growth ofCryptomeria japonica and have an excellent effect of inhibiting theformation of male flowers thereof.

The prohexadione compounds include, for example, the followingcompounds:(I) cyclohexanedioncarboxylic acid derivatives of the following formulaAI:

wherein:

-   A represents an —OR₂ or —NR₃R₄,-   B represents a hydroxyl group, an —NHOR₁ group or a salt thereof,-   R represents an alkyl group having 1 to 6 carbon atoms or a    cycloalkyl group having 3 to 6 carbon atoms, the alkyl or cycloalkyl    group being unsubstituted or substituted with a halogen atom, an    alkoxyl group having 1 to 6 carbon atoms or an alkylthio group    having 2 to 4 carbon atoms,-   R₁ represents an alkyl group having 1 to 6 carbon atoms, a haloalkyl    group having 1 to 6 carbon atoms, an alkenyl group having 3 to 6    carbon atoms, a haloalkenyl group having 3 to 6 carbon atoms or an    alkynyl group having 3 to 6 carbon atoms, and-   R₂, R₃ and R₄ independently represent a hydrogen atom, an alkyl    group having 1 to 6 carbon atoms, a haloalkyl group having 1 to 6    carbon atoms, an alkoxyalkyl group having 2 to 10 carbon atoms, an    alkylthioalkyl group having 2 to 10 carbon atoms, an alkenyl group    having 3 to 6 carbon atoms, which group may be substituted with a    halogen atom, an alkoxyl group having 1 to 4 carbon atoms or an    alkylthio group having 1 to 4 carbon atoms, an alkynyl group having    5 or 6 carbon atoms, or a phenyl group or an aralkyl group having 1    to 6 carbon atoms wherein the phenyl nucleus may be substituted with    a halogen atom, an alkyl group having 1 to 4 carbon atoms, an    alkoxyl group having 1 to 4 carbon atoms, a haloalkyl group having 1    to 4 carbon atoms, a nitro group or a cyano group, and-   R₃ and R₄ may form a 5- or 6-membered heterocyclic ring together    with the carbon atom to which they are bonded and the ring may    further contain a carbon atom or sulfur atom.

In the above-described definition, the alkyl groups may be either linearor branched, and they include, for example, methyl group, ethyl group,propyl group, isopropyl group, butyl group, isobutyl group, secondarybutyl group, tertiary butyl group and all the stereoisomers of higherhomologues thereof. The alkenyl groups and alkynyl groups may be eitherlinear or branched, and they include, for example, vinyl group, allylgroup, methallyl group, butenyl group, methylbutenyl group,dimethylbutenyl group, ethynyl group, propynyl group, butynyl group,methylbutynyl group and dimethylbutynyl group.

The halogen atom represents fluorine atom, chlorine atom, bromine atomor iodine atom.

The ring may further contain an oxygen atom or a sulfur atom. The 5- or6-membered heterocyclic —NR₃R₄ may be a pyrrole, pyrrolidine,piperidine, morpholine or thiomorpholine ring or the like. Such a ringmay be substituted with a methyl group.

Salts of these compounds (including ammonium salts thereof) are obtainedby the reaction of them with a base. The preferred bases are, forexample, alkali metal hydroxides; alkaline earth metal hydroxides; iron,copper, nickel and zinc hydroxides; ammonia; alkylammoniums having 1 to4 quaternary carbon atoms; and hydroxyalkylammonium bases having 1 to 4carbon atoms.

In the cyclohexanedioncarboxylic acid derivatives of general formula AI,particularly effective compounds are those of the following groups:Cyclohexane derivatives of the following formula Ala and salts thereof,preferably metal salts or ammonium salts thereof:

wherein A and R are as defined above;

-   The derivatives of above formula AIa wherein A represents an —OR₂    and R and R₂ are as defined above, and metal salts or ammonium salts    thereof;-   The derivatives of above formula AIa wherein A represents an —NR₃R₄    and R, R₃ and R₄ are as defined above, and metal salts or ammonium    salts thereof; and-   The derivatives of above formula AIa wherein A is as defined above,    and R represents a cycloalkyl group having 3 to 6 carbon atoms, and    metal salts or ammonium salts thereof.-   Further effective compounds are cyclohexanedions of the following    formula Alb and metal salts or ammonium salts thereof:    wherein A, R and R₁ are as defined above;-   The derivatives of above formula AIb wherein A represents an —OR₂    and R, R₁ and R₂ are as defined above, and metal salts or ammonium    salts thereof; and-   The derivatives of above formula AIb wherein A represents an —NR₃R₄,    and R, R₁, R₃ and R₄ are as defined above, and metal salts or    ammonium salts thereof.

Examples of the preferred compounds are as follows:

-   ethyl 4-butyryl-3,5-cyclohexanedioncarboxylate,-   isobutyl 4-butyryl-3,5-cyclohexanedioncarboxylate,-   ethyl 4-(1-ethoxyaminobutylidene)-3,5-cyclohexanedioncarboxylate,-   ethyl 4-(1-allyloxyaminobutylidene)-3,5-cyclohexanedioncarboxylate,-   ethyl    4-(1-cyclopropylhydroxymethylidene)-3,5-cyclohexanedioncarboxylate,-   isobutyl    4-(1-allyloxyaminobutylidene)-3,5-cyclohexanedioncarboxylate,-   dimethyl 4-(1-ethoxyaminobutylidene)-3,5-cyclohexanedioncarboxamide,-   dimethyl    4-(1-allyloxyaminobutylidene)-3,5-cyclohexanedioncarboxamide,-   diethyl    4-(1-allyloxyaminobutylidene)-3,5-cyclohexanedioncarboxamide,-   benzyl 4-(1-ethoxyaminobutylidene)-3,5-cyclohexanedioncarboxamide    and-   sodium, ammonium and tetramethylammonium salts of them.

The cyclohexanedioncarboxylic acid derivatives of above formula AI canbe obtained in the form of, for example, various tautomers as shownbelow:

The cyclohexanedioncarboxylates of formula AI are produced by reacting a3,5-cyclohexanedioncarboxylic acid derivative of the following formulaII:

wherein A represents the above-described ester or amido group, with anacid halide of the following formula III:Hal-COR  (III)wherein R is as defined above,in the presence of a base as an acid acceptor in an inert organicsolvent, then isolating the product thus obtained and, if desired,reacting the product with a hydroxylamine of the following formula IV:HONHR₁  (IV)wherein R₁ is as defined above,in an inert water-immiscible solvent at the boiling temperature undercondensation conditions, and isolating the resultant product.

The solvents particularly suitable for the reaction are, for example,aromatic hydrocarbons such as benzene, toluene and xylene, and alsohalogenated hydrocarbons such as chloroform, dichloroethane and carbontetrachloride.

The reaction temperature is in the range of room temperature to theboiling point of the reaction mixture. It might be necessary to cool thereaction vessel while the acid chloride is added.

Suitable acid acceptors are organic and inorganic bases such aspyridine, 4-aminopyridine, collidine, triethylamine, ammonium, as wellas sodium, potassium and calcium carbonates and correspondingbicarbonates.

The suitable acid halides of formula III are mainly acetyl chloride,propionyl chloride, butyryl chloride, valeryl chloride,3-methoxypropionyl chloride, 2-chloropropionyl chloride, cyclopropanoylchloride and cyclohexanoyl chloride, as well as corresponding bromides.

The suitable hydroxylamines of formula IV are particularly methyl-,ethyl-, chloroethyl-, propyl-, isopropyl-, butyl-, isobutyl-, allyl-,cycloallyl-, methallyl- and propinylhydroxylamines. They can be used inthe form of salts such as hydrochlorides thereof.

The cyclohexauedioncarboxylic acid derivatives of formula II used as thestarting materials can also be obtained by hydrogenating3,5-dihydroxybenzoic acid with hydrogen in the presence of Raney nickeland then esterifying or amidating the acid group thereof according tothe following reaction scheme:

In the above formulae, the keto group must be protected in the form ofan enol ether or an enamine [refer to J. Am. Chem. Soc. 78, 4405(1956)].

In addition, 3,5-dihydroxybenzoic acid derivatives can be hydrogenatedwith hydrogen in the presence of Raney nickel according to the followingreaction formula:

[refer to Arch. Pharm. 307, 577 (1974)].(II) Cyclohexane compounds of the following formula BI and saltsthereof:

wherein R represents a hydrogen atom or an alkyl group, and R¹represents an alkyl group.

These compounds are disclosed in the specification of JP Kokai No. Hei4-29659. However, this specification only discloses plant growthregulators containing such a compound, and it does not disclose norsuggest any use of the compounds as agents for inhibiting the formationof Cryptomeria japonica pollen which do not substantially inhibit theelongation growth of Cryptomeria japonica and have an excellent effectof inhibiting the formation of male flowers thereof.

Concrete examples of those compounds are as follows:

-   Compounds of the following formula BIa:-   Compounds of the following formula BIb:-   Compounds of the following formula BIc:    wherein R and R¹ are as defined above, and M represents an organic    or inorganic cation.

The alkyl groups are, for example, methyl group, ethyl group, propylgroup and butyl group. The organic or inorganic cations are, forexample, cations of metals such as alkali metals, alkaline earth metals,aluminum, copper, nickel, manganese, cobalt, zinc, iron and silver, andammonium ions of the formula:

wherein R³, R⁴, R⁵ and R⁶ each represents a hydrogen atom, an alkylgroup, a hydroxyalkyl group, an alkenyl group, benzyl group, a benzylgroup substituted with a halogen atom, a pyridyl group or a pyridylgroup substituted with an alkyl group, and R³ and R⁴ may together form apolymethylene group or a polymethylene group with an oxygen atom betweenthem.

Those compounds can be produced by the following processes:

wherein R² represents an alkyl group, M¹ represents an alkali metalatom, and R and R¹ are as defined above.

Namely, compounds [BIe] can be produced by reacting a compound [BId] or[BIf] with an acid chloride in the presence or absence of γ-picoline andalso in the presence or absence of a base in a solvent at a temperaturein the range of −20° C. to the boiling point of the solvent, preferablynot higher than room temperature for 10 minutes to 7 hours. The basescan be selected from those usually used for dehydrohalogenationreactions. The bases are organic bases such as trimethylamine,triethylamine, tripropylamine, tributylamine, pyridine andN,N-dimethylaminopyridine, and inorganic bases such as sodium hydroxide,potassium hydroxide, sodium carbonate, potassium carbonate and sodiumhydrogencarbonate. The solvents are organic solvents such as toluene,benzene, xylene, dichloromethane, 1,2-dichloroethane, chloroform, carbontetrachloride, N,N-dimethylformamide, dimethyl sulfoxide and methylcellosolve and/or water. γ-Picoline is also considered to have an effectof phase-transfer catalyst.

Compounds [BI] can be produced by reacting a compound [BIe] in thepresence of a catalyst in a solvent at a temperature in the range ofroom temperature to the boiling point of the solvent for 1 to 10 hours[formula (3)]. The catalysts include pyridine derivatives such as4-N,N-dimethylaminopyridine, 4-N,N-diethylaminopyridine and4-pyrrolidinoaminopyridine; and N-alkylimidazole derivatives such asN-methylimidazole and N-ethylimidazole.

The compounds [BI] can be produced without isolating the intermediates[BIe].

The compounds [BI] can also be produced by reacting a compound [BIg]with a halogenating agent in the presence or absence of a base in asolvent or without any solvent at a temperature in the range of −20° C.to a boiling point of the solvent or halogenating agent, preferably inthe range of −10° C. to 100° C. for 10 minutes to 7 hours to halogenatethe compound [BIg] and then reacting the resultant product with analcohol of the formula: R₂OH in the presence or absence of a base at atemperature in the range of −20° C. to 100° C. for 10 minutes to 48hours. The solvents used for the halogenation include, for example,dichloromethane, chloroform, carbon tetrachloride, benzene, toluene andxylene. The base used for the halogenation or esterification can beselected from those usually used for the dehydrohalogenation reactions.The bases include organic bases such as triethylamine, pyridine,N,N-dimethylaminopyridine and N,N-dimethylaniline; and inorganic basessuch as sodium hydroxide, potassium carbonate and sodiumhydrogencarbonate. The halogenating agents include, for example, thionylchloride, phosphorus trichloride, phosphorus pentachloride andphosphorus oxychloride. A halide of the intermediate can also beisolated and esterified.

Salts of the above-described compounds can be produced as follows:Organic or inorganic salts can be produced by reacting a compound ofgeneral formula [BI] with an equivalent or 2 or higher equivalents of aprimary amine; a secondary amine; a tertiary amine; an alcoholate; or achloride, hydride, hydroxide, sulfate, nitrate, acetate or carbonate ofa metal such as sodium, potassium, calcium, magnesium, barium, aluminum,nickel, copper, manganese, cobalt, zinc, iron or silver; in an organicsolvent. When they are reacted with each other in equivalent amounts,the obtained salt is in the form of the formula [BIa] in case R in theformula [BI] is other than hydrogen atom, and the obtained salt is inthe form of the formula [BIb] in case R is hydrogen atom. When such acompound is used in an amount of 2 equivalents or more, the resultantcompound is in the form of the formula [BIc].

Those compounds can be represented by the following tautomericstructural formulae:

wherein Z represents R or M, and R, M and R¹ are as defined above.(III) Cyclohexane compounds of the following formula CI or saltsthereof:

wherein R¹ represents a hydrogen atom or a lower alkyl group, R²represents a lower alkyl group, and R³ represents a hydrogen atom, analkyl group, an alkenyl group, a hydroxyalkyl group, a cycloalkyl group,morpholino group, an aminoalkyl group, an N-alkylaminoalkyl group, anN,N-dialkylaminoalkyl group, an alkoxycarbonylalkyl group, a group ofthe formula:—(CH₂)₁R⁴(wherein R⁴ represents a lower alkoxyl group, a lower alkylthio group, abenzylthio group, an anilino group, a morpholino group, a piperazinogroup or a piperidino group which may be substituted with a lower alkylgroup, and 1 represents an integer of 2 or 3),a group of the formula:

(wherein X represents a halogen atom, a lower alkyl group, a loweralkoxyl group, phenoxy group or an alkoxycarbonylalkyloxy group, mrepresents an integer of 0 or 1, and n represents an integer of 0 to 2),a group of the formula:—CH₂R⁵(wherein R⁵ represents a furyl group, a thenyl group or a pyridylgroup), ora group of the formula:

(wherein R⁵ is as defined above).

Those compounds are disclosed in JP-Kokai No. Hei 6-76356. However, thespecification thereof discloses only the plant growth regulatorscontaining those compounds and it does not disclose nor suggest any useof those compounds as agents for inhibiting the formation of Cryptomeriajaponica pollen, which do not substantially inhibit the elongationgrowth of Cryptomeria japonica and which have an excellent effect ofinhibiting the formation of male flowers thereof.

Although the present invention is primarily exemplified by beingdescribed in terms of a method for using prohexadione compounds forinhibiting the formation of Cryptomeria japonica pollinosis, thoseskilled in the art will appreciate that the methods and composition ofthe present invention also are suitable for inhibiting pollinosis inother plants of the division Coniferophyta and, in particular, in plantsof the class Pinopsida including, for example: from the familyAraucariaceae, for example, Agathis Salisb. spp., Araucaria Juss. spp.and Wollemia W. (W. nobilis); from the family Cephalotaxaceae, forexample, Cephalotaxus Siebold & Zucc. spp.; from the familyCupressaceae, for example, Actinostrobus Miq. spp., Austrocedrus Florin& Boutelje spp. (A. chilensis), Callitris Vent. spp., Calocedrus Kurz.spp, Chamaecyparis Spach. spp., Cupressus L. spp., Diselma Hook.f. spp.(D. archeri), Fitzroya Hook.f. ex Lindl. spp. (F. cupressoides),Fokienia A.Henry & H. H. Thomas. spp. (F. hodginii), Juniperus L. spp.,Libocedrus Endl. spp., Microbiota Kom. spp. (M. decussata),Neocallitropsis Florin. spp. (N. pancheri), Pilgerodendron Florin. spp.(P. uviferum), Tetraclinis Mast. spp. (T. arliculata), Thuja L. spp.,Thujopsis Siebold & Zucc. ex Endl. spp. (T. dolabrata), WiddringtoniaEndl. spp.; from the family Pinaceae, for example, Abies Mill. Ca. spp.,Cathaya Chun & Kuang. spp. (C. argyrophylla Chun & Kuang), Cedrus Trew.spp., Keteleeria Carriere. spp., Larix Mill. spp., Nothotsuga Hu exC.N.Page. spp. (N. longibracteata), Picea A. Dietr. spp., Pinus L. spp.,Pseudolarix Gordon. spp. (P. amabilis), Pseudotsuga Carriere. spp.,Tsuga Carriere. spp.; from the family Podocarpaceae, for example,Acmopyle Pilg. spp., Dacrycarpus (Endl.) de Laub. spp., Dacrydium Lamb.spp., Falcatifolium de Laub. spp.; from the family Taxaceae, forexample, Amentotaxus Pilg. spp., Taxus L. spp., Torreya Arn. spp.; fromthe family Taxodiaceae, for example, Athrotaxis D. Don. spp.,Cryptomeria D.Don. spp. (especially Cryptomeria japonica), CunninghamiaR.Br. spp.; Glyptostrobus Endl. spp. (G. pensilis); Sciadopitys Siebold& Zucc. spp. (S. verticillata), Sequoia Endl. spp. (S. sempervirens),Sequoiadendron Buchholz. spp. (S. giganteum), Taiwania Hayata. spp.,Taxodium Rich. spp; from the family Phyllocladaceae, for example,Phyllocladus Rich. ex Mirb. spp.

The compounds of the formula [CI] can have the following tautomericstructures:

Further, the compounds of the formula CI can form salts thereof, whichare also included in the scope of the present invention.

Concrete examples of the above-described compounds are shown below.TABLE 1

(1) R¹ R² R³ (2) 1 CH₃ CH₃ CH₃ 91˜93° C. 2 ″ ″ C₂H₅ 76.5˜78.5° C. 3 C₂H₅C₂H₅ ″ n_(D) ²⁰1.5348 4 ″ n-C₃H₇ ″ n_(D) ²⁰1.5275 5 CH₃ ″ n-C₃H₇ n_(D)²⁰1.5288 6 ″ C₂H₅ ″ 55˜57° C. 7 C₂H₅ ″ i-C₃H₇ n_(D) ²⁰1.5246 8 i-C₂H₇ ″″ n_(D) ²⁰1.5155 9 C₂H₅ ″ seo-C₄H₅ n_(D) ²⁰1.5249 10 ″ ″ —C₂H₄NHC₂H₅n_(D) ²⁰1.5269 11 ″ ″ —C₂H₅NHCH₃ n_(D) ²⁰1.5368 12 ″ ″

n_(D) ²⁰1.5169 13 ″ ″ —C₂H₅N(C₅-n)₂ n_(D) ²⁰1.5133 14 ″ ″ —C₂H₄OH n_(D)²⁰1.5474 15 ″ ″ —(CH₂)₅OH n_(D) ²⁰1.5379 16 ″ ″

n_(D) ²⁰1.5730 17 ″ ″

56˜58° C. 18 ″ ″

n_(D) ²⁰1.5801 19 ″ ″

61˜62° C. 20 ″ ″

108˜110° C. 21 CH₃ ″ ″ 146˜147° C. 22 ″ CH₃ ″ 118˜119° C. 23 C₂H₅ ″ ″122˜123° C. 24 CH₃ n-C₃H₇ ″ 83˜84° C. 25 ″ C₂H₅

83˜84° C. 26 C₂H₅ ″ ″ n_(D) ²⁰1.5738 27 ″ ″

n_(D) ²⁰1.5760 28 ″ ″

79˜80° C. 29 ″ ″

91˜93° C. 30 ″ ″

82˜83° C. 31 ″ ″

90˜92° C. 32 H ″

205˜207° C. 33 HOCH₃CH₃NH₃ ″ —CH₂CH₂OH 118˜119° C. 34 C₂H₅ n-C₂H₇—C₂H₄OH n_(D) ²⁰1.5258 35 ″ ″

n_(D) ²⁰1.5360 36 ″ C₂H₅ CH₃ n_(D) ²⁰1.5368 37 ″ ″ n-C₄H₇ n_(D) ²⁰1.527538 CH₃ ″ —C₂H₄OH n_(D) ²⁰1.5570 39 C₂H₅ ″ —C₃H₅OH n_(D) ²⁰1.5381 40 ″CH₃ —C₂H₄OH n_(D) ²⁰1.5325 41 ″ C₂H₅

n_(D) ²⁰1.5291 42 ″ ″

81˜82° C. 43 ″ ″

93.5˜95.5° C. 44 ″ ″

76˜78° C. 45 ″ ″

81˜82° C. 46 ″ ″

n_(D) ²⁰1.5385 47 CH₄ ″ i-C₂H₇ n_(D) ²⁰1.5338 48 C₂H₅ ″

n_(D) ²⁰1.5790 49 ″ ″

49˜51° C. 50 ″ ″

n_(D) ²⁰1.5648 51 ″ ″

 99˜101° C. 52 CH₃ n-C₄H₇ CH₃ n_(D) ²⁰1.5385 53 ″ ″ C₂H₅ n_(D) ²⁰1.527854 ″ ″ i-C₃H₇ n_(D) ²⁰1.5225 55 ″ ″

n_(D) ²⁰1.5598 56 ″ C₂H₅ CH₃ 716˜72° C. 57 ″ ″ C₂H₅ n_(D) ²⁰1.5457 58C₂H₅ ″ n-C₃H₇ 48˜49° C. 59 ″ n-C₃H₇ CH₃ n_(D) ²⁰1.5373 60 ″ ″ n-C₂H₇n_(D) ²⁰1.5273 61 ″ ″ i-C₂H₇ n_(D) ²⁰1.5261 62 ″ ″

82˜83° C. 63 ″ ″

n_(D) ²⁰1.5692 64 ″ CH₃ CH₃ 74˜75° C. 65 ″ ″ C₂H₅ 49˜50° C. 66 ″ ″n-C₂H₇ 58˜59° C. 67 ″ ″ i-C₂H₇ 55˜58° C. 68 ″ ″

95˜96° C. 69 CH₃ ″ n-C₂H₇   56˜57.5° C. 70 ″ ″ i-C₂H₇ 41˜42° C. 71 ″ ″

138˜140° C. 72 C₂H₅ C₂H₄ i-C₄H₅ n_(D) ²⁰1.5252 73 n-C₃H₇NH₃ ″ n-C₄H₅n_(D) ²⁰1.5322 74

″

140˜143° C. 75 C₃H₅ ″ H 69˜71° C. 76 ″ ″ —C₂H₄OCH₃ n_(D) ²⁰1.5332 77 ″ ″—C₃H₅OCH₃ n_(D) ²⁰1.5266 78 ″ ″

n_(D) ²⁰1.5413 79 ″ ″

n_(D) ²⁰1.5440 80 ″ ″

n_(D) ²⁰1.5855 81 ″ ″

67˜68° C. 82 ″ ″

103˜105° C. 83 ″ ″

97˜99° C. 84 ″ ″

154˜156° C. 85 ″ ″

117˜119° C. 86 ″ ″

165˜167° C. 87 ″ ″

n_(D) ²⁰1.5513 88 ″ ″

n_(D) ²⁰1.5832 89 ″ ″

n_(D) ²⁰1.5702 90 ″ ″ —C₂H₄SCH₃ n_(D) ²⁰1.5600 91 ″ ″

n_(D) ²⁰1.5835 92 ″ ″

n_(D) ²⁰1.5338 93 ″ ″

n_(D) ²⁰1.5318 94 ″ ″

n_(D) ²⁰1.5333 95 ″ ″

182˜184° C. 96 ″ ″ —CH₃CH—CH₂ n_(D) ²⁰1.5428 97 ″ ″

86˜88° C. 98 ″ ″

75˜77° C. 99 ″ ″

n_(D) ²⁰1.5815 100 ″ ″

n_(D) ²⁰1.5506 101

″

128˜130° C. 102

″

213˜215° C. 103

″

128˜130° C. 104 i-C₃H₇NH₃ ″ —C₃H₇-i 120˜128° C. 105 n-C₄H₃NH₃ ″ —C₄H₅-n117˜121° C. 106

″

53˜56° C. 107 CH₃O(CH₃)₃NH₃ ″ —(CH₃)₂OCH₃ 63˜65° C. 108 i-C₃H₇O(CH₂)₃NH₃″ —(CH₂)₃OC₂H₇-i 67.5˜70.5° C.*(1) Compound No.(2) Melting Point or Index of Refraction

Compounds of the above formula CI can be produced by, for example, thefollowing method:

wherein R₁, R² and R₃ are as defined above. However, when R¹ in theformula [II] is hydrogen atom, R¹ in the formula [I] represents R³NH₃.Further, when R¹ in the formula [II] is a hydrogen atom and R³ in theformula [I] and [III] represents a group of the following formula:

wherein X and m are as defined above,R¹ in the formula [I] represents a hydrogen atom.

Namely, the intended compounds can be produced by reacting a compound ofthe formula [II] with an amine of the formula [III] in a solvent orwithout any solvent at a temperature in the range of room temperature tothe boiling point of the solvent for 0.1 to 10 hours The solventsinclude alcoholic solvents such as methanol and ethanol, non-polarsolvents such as benzene, toluene and xylene; acetic ester solvents suchas methyl acetate and ethyl acetate, and halogenated hydrocarbonsolvents such as dichloromethane and chloroform.(IV) Cyclohexanecarboxylic acid derivatives of the following formula DIand salts thereof:

wherein R¹ represents a hydrogen atom, a lower alkyl group or phenylgroup, X represents an oxygen atom or a sulfur atom, R² represents ahydrogen atom, an alkyl group, an alkenyl group, an alkylthioalkylgroup, an alkoxycarbonylmethyl group, a benzyl group substituted with ahalogen atom, a group of the formula:

(wherein Y represents a carbonyl group, a sulfonyl group or a sulfonategroup, Z represents a hydrogen atom, a halogen atom, a lower alkylgroup, a lower alkoxyl group, a cyano group or a trifluoromethyl group,m represents 0 or 1, and n represents an integer of 1 or 2, with theproviso that when n represents 2, Z may be a combination of differentgroups or atoms),a furyl group or a thienyl group.

Those compounds are disclosed in Japanese Patent No. 2,696,252. However,the specification thereof discloses only herbicides and plant growthregulators containing those compounds and it does not disclose norsuggest any use of those compounds as agents for inhibiting theformation of Cryptomeria japonica pollen, which do not substantiallyinhibit the elongation growth of Cryptomeria japonica trees and whichhave an excellent effect of inhibiting the formation of male flowersthereof.

Examples of the compounds of the above formula DI are shown in Table 2.TABLE 2

(3) R¹ X R² (4) 1 H O

223-225 2 CH₃ O H 115-118 3 CH₃ O CH₃ 101-102 4 CH₃ O C₃H₅ 47-49 5 CH₃ OC₃H₇-n 68-69 6 CH₃ O C₃H₇-i 43-45 7 CH₃ O CH₃CH═CH₂ 68-69 8 CH₃ O C₃H₅-n47-48 9 CH₃ O CH₃CH₂SCH₃ 52-54 10 CH₃ O CH₃COOC₃H₅ 69-71 11 CH₃ O

112-114 12 CH₃ S CH₃ 73-74 13 CH₃ S C₂H₅ 59-60 14 CH₃ S CH₂CH═CH₂ 1.581615 CH₃ O

122-123 16 CH₃ O

113-114 17 CH₃ O

155-156 18 CH₃ O

121-122 19 CH₃ O

160-162 20 CH₃ O

154-155 21 CH₃ O

122-123 22 CH₃ O

128-130 23 CH₃ O

140-141 24 CH₃ O

140-142 25 CH₃ O

151-153 26 CH₃ O

134-136 27 CH₃ O

90-91 28 CH₃ S

110-112 29 C₂H₅ O

156-157 30

O

157-158 31 CH₃ O

149-151 32 CH₃ O

1.5485 33 CH₃ O

96-98*(3)Compound No.(4) Melting Point (° C.) or Index of Refraction(n_(D) ²⁰)

Those compounds can be produced by, for example, the following method:

wherein R¹, R² and X are as defined above.

Namely, the compounds of the general formula [IV] can be obtained byreacting a compound of the formula [II] with an isocyanate orisothiocyanate of the formula [III] in the presence of a base in asolvent or without any solvent and then depositing the product with anacid. The compounds of the formula [V] can be easily obtained from thecompounds of the formula [IV] by treating the latter with an aqueousalkali solution.

The compounds of the formula [VI] can be easily obtained by reacting acompound of the formula [II] with urea, chlorosulfonyl isocyanate or thelike. Those reactions are conducted at a temperature of, for example, 0to 130° C., preferably 20 to 80° C. However, the reaction of a compoundof the formula [II] with urea is desirably conducted without any solventat 100 to 130° C.

The preferred bases include inorganic bases such as sodium hydroxide,potassium hydroxide, metallic sodium, sodium hydride, potassiumcarbonate and sodium hydrogencarbonate; and tertiary organic amines suchas trimethylamine, triethylamine, N,N-dimethylaniline, pyridine,substituted pyridines and diazabicycloundecene (DBU). The solvents aresuitably selected from those which do not participate in the reaction,such as N,N-dimethylformamide, N,N-dimethylacetamide, dimethylsulfoxide, hexamethylene phosphoroamide, acetonitrile, tetrahydrofuran,benzene, toluene, xylene, ethyl ether, dichloromethane, dichloroethaneand chloroform. The compounds represented by the formula [II] are wellknown and processes for producing them are described in, for example,the specifications of JP Kokai Nos. Sho 58-164543 and Sho 59-231045.

The prohexadione compounds of the present invention are used as they areor preferably in the form of a composition with an ordinary adjuvantused in the preparation techniques. These compounds are used to form,for example, an undiluted emulsion, a film-forming paste, a solutionwhich can be directly sprayed or diluted, a diluted emulsion, a wettablepowder, a water-soluble powder, a dust, granules and capsules preparedby the encapsulation with a polymer. The properties of the compositionand also the method for the application thereof such as spraying,dusting, sprinkling or injection are selected depending on theCryptomeria japonica and the environmental conditions.

When the agent of the present invention for inhibiting the formation ofCryptomeria japonica pollen is to be applied to Cryptomeria japonicatrees in a large area of at least several ares such as in an afforestedarea, for example, curtain application method with a helicopter issuitable.

A suitable solid or liquid adjuvant may be used, if necessary, togetherwith the prohexadione compound. Such a preparation or composition isproduced by, for example, homogeneously mixing and/or grinding theprohexadione compound as the active ingredient with a filler such as asolvent, a solid carrier and, if necessary, a surface-activatingcompound (surfactant) by a well-known method.

The suitable solvents are as follows:

-   aromatic hydrocarbons preferably having 8 to 12 carbon atoms such as    xylene mixtures and substituted naphthalene; phthalates such as    dibutyl phthalate and dioctyl phthalate; aliphatic hydrocarbons such    as cyclohexane and paraffin; alcohols and glycols and their ethers    and esters such as ethanol, ethylene glycol monomethyl or monoethyl    ether; ketones such as cyclohexanone; strong polar solvents such as    N-methyl-2-pyrrolidone, dimethyl sulfoxide and dimethylformamide;    epoxidized vegetable oils such as epoxidized coconut oil and    epoxidized soybean oil; and water.

Solid carriers usable for the dusts and dispersible powders are usuallypreferably natural mineral fillers such as calcite, talc, kaolin,montmorillonite and attapulgite. For improving the physical propertiesof the preparation, for example, highly dispersible silicic acid orhighly dispersible, absorbable polymer can be added thereto. Thesuitable granulated absorbing carriers are porous ones such as pumice,crushed bricks, sepiolite and bentonite. The suitable non-absorbingcarriers are, for example, calcite and sands. Further, various,previously granulated inorganic and organic substances, particularlydolomite and pulverized plant residues are preferred.

Suitable surface-activating compounds, which vary depending on theproperties of the prohexadione compounds of the present invention, arenon-ionic, cationic and anionic surfactants having excellent emulsifyingproperty, dispersing property and wetting property.

The term “surfactants” also includes surfactant mixtures.

Suitable anionic surfactants are, for example, water-soluble soaps,water-soluble synthetic surface-activating compounds and mixtures ofthem.

Suitable soaps are, for example, alkali metal salts, alkaline earthmetal salts and unsubstituted or substituted ammonium salts of higherfatty acids (C10 to C12); such as sodium and potassium salts of oleicacid, stearic acid and natural fatty acid mixtures obtained from coconutoil and tallow. Methyltaurine salts of fatty acids are also usable.

So-called synthetic surfactants such as aliphatic sulfonates, aliphaticsulfates, sulfonated benzimidazole derivatives and alkylaryl sulfonatesare often used.

The aliphatic sulfonates and sulfates are usually in the form of alkalimetal salts, alkaline earth metal salts and unsubstituted or substitutedammonium salts thereof. They contain an alkyl group having 8 to 22carbon atoms including the alkyl moiety of the acyl groups thereof.Examples of them include sodium and calcium salts of lignosulfonic acid,dodecyl sulfate and aliphatic alcohol sulfates obtained from naturalfatty acids. Those compounds include salts of sulfuric acid esters andsulfonic acid salts of aliphatic alcohol/ethylene oxide adducts.

Sulfonated benzimidazole derivatives preferably contain two sulfonicacid groups and a fatty acid group containing 8 to 22 carbon atoms.Examples of the alkylaryl sulfonates include sodium, calcium andtriethanolamine salts of dodecylbenzenesulfonic acid ornaphthalenesulfonic acid/formaldehyde condensate. Correspondingphosphates such as salts of phosphoric acid esters of p-nonylphenyladducts containing 4 to 14 mols of ethylene oxide, and phospholipids arealso suitable.

The nonionic surfactants are preferably polyglycol ether derivatives ofaliphatic or alicyclic alcohols or saturated or unsaturated fatty acidalkylphenols. Those derivatives contain 3 to 30 glycol ether groups, 8to 20 carbon atoms in the (aliphatic) hydrocarbon moiety and 6 to 18carbon atoms in the alkyl moiety of the alkylphenyl.

Other suitable nonionic surfactants are, for example, water-solubleadducts of polyethylene oxide and polypropylene glycol,ethylenediaminepolypropylene glycol or an alkylpolypropylene glycolhaving 1 to 10 carbon atoms in the alkyl chain. The adducts contain, forexample, 20 to 250 ethylene glycol ether groups and 10 to 100 propyleneglycol ether groups. These compounds usually contain 1 to 5 ethyleneglycol units per propylene glycol unit.

Typical examples of the nonionic surfactants include nonylphenol/polyethoxyethanol, castor oil polyglycol ether,polypropylene/polyethylene oxide adduct,tributylphenoxypolyethoxyethanol, polyethylene glycol andoctylphenoxyethoxyethanol. Further, fatty acid esters ofpolyoxyethylenesorbitans and polyoxyethylenesorbitan trioleates are alsosuitable nonionic surfactants.

The cationic surfactants are preferably quaternary ammonium salts havingat least one alkyl group having 8 to 22 carbon atoms as theN-substituent and also an unsubstituted or halogenated lower alkylgroup, benzyl group or a lower hydroxyalkyl group as the othersubstituent. The salts are preferably halides, methyl sulfates or ethylsulfates. They are, for example, stearyltrimethylammonium chloride andbenzyl di-(2-chloroethyl)ethylammonium bromide.

The surfactants usually used in the pharmaceutical field are describedin, for example, the following publications: Mc Cutcheon's Detergentsand Emulsifiers Annual, Mac Publishing Co., Lingwood, N.J., 1981; H.Stache, Tensid-Tashen-buch, 2^(nd) Edition, C. Hanser Verlag, Munchenand Vienna, 1981; M. and J. Ash, Encyclopedia of Surfactants, Vols. I toII, Chemical Publishing Co., New York, 1980-1981.

The agent of the present invention for inhibiting the formation ofCryptomeria japonica pollen usually contains 0.1 to 95%, preferably 0.1to 80%, of a prohexadione compound, 1 to 99.9% of solid or liquidadjuvants and 0 to 25%, preferably 0.1 to 25%, of a surfactant.

Preferred preparations are those comprising the following components(the percentages are given by mass):

Undiluted Emulsion

-   -   active ingredient: 10 to 20%, preferably 5 to 10%    -   surfactant: 5 to 30%, preferably 10 to 20%    -   liquid carrier: 50 to 94%, preferably 70 to 85%        Dust    -   active ingredient: 0.1 to 10%, preferably 0.1 to 1%    -   solid carrier 99.9 to 90%, preferably 99.9 to 99%        Undiluted Suspension    -   active ingredient: 5 to 75%, preferably 10 to 60%    -   water: 94 to 25%, preferably 90 to 30%    -   surfactant: 1 to 40%, preferably 2 to 30%        Wettable Powder    -   active ingredient: 0.5 to 90%, preferably 1 to 60%    -   surfactant: 0.5 to 20%, preferably 1 to 15%    -   solid carrier: 5 to 90%, preferably 15 to 90%        Granules    -   active ingredient: 0.5 to 30%, preferably 3 to 15%    -   solid carrier: 99.5 to 70%, preferably 97 to 85%

The prohexadione compounds may be formulated in the form of aconcentrated preparation. In this case, the users usually dilute theconcentrated preparation before use.

The preparation can be diluted to a concentration as low as 0.001%. Theapplication rate is usually 0.01 to 10 kg active ingredient (a.i.)/ba,preferably 0.025 to 5 kg a.i./ba.

If necessary, the preparation or the composition thereof can containother components such as a stabilizer, an antifoaming agent, a viscositymodifier, a binder, a thickening agent, a fertilizer and other activeingredients having other special effects.

The following Examples and Comparative Examples will further illustratethe present invention.

EXAMPLE 1

Effect of a Prohexadione Compound of the Following Chemical Structure on8-year Old Young Cryptomeria japonica Trees:

(Materials and Method)

Two 8-year old young Cryptomeria japonica trees (height: 8 m, diameterat breast height: 6 cm) which were in a nursery of an experimentalplantation of the department of agriculture of Tottori University andwhich had formed male flowers every year were used. Three branches wereselected at male flower-forming positions of each tree. These brancheswhich were supposed to form the male flowers were treated with theprohexadione compound (treatment with the undiluted powder) on Jun. 5,2001 (about one month before the beginning of July when Cryptomeriajaponica flower buds were supposed to differentiate and Cryptomeriajaponica flower buds were supposed to be formed). In this test, theprohexadione compound was diluted to a concentration shown in Table 3given below with 60% (v/v) aqueous acetone solution.

The treatment method was as follows: 100 ml of the diluted solutionobtained as described above was sprayed on leaves of the branches (50 cmlong area from the branch top) with a hand sprayer. In a control group,the leaves were treated with only 60% (v/v) aqueous acetone solution.

The concentrations of the prohexadione compound used for the foliarspray treatment were as follows:

Concentration (ppm)

-   -   0.5    -   5    -   50    -   500        Results        (1) Effect on the Differentiation and Formation of Male        Cryptomeria japonica Flowers

Table 4 given below shows the effect of the treatment with the undilutedprohexadione compound on the male flower formation of the 8-year oldyoung Cryptomeria japonica trees. It will be clear from Table 4 that thedifferentiation and formation of male flower buds were remarkable in thecontrol group. On the other hand, when the agent of the presentinvention for inhibiting the formation of Cryptomeria japonica pollenwas used, the differentiation and formation of male flower buds wereinhibited. Particularly when the concentration of the prohexadionecompound used for the treatment was 50 ppm or 500 ppm, the effect ofinhibiting the differentiation and formation of male Cryptomeriajaponica flowers was remarkable.

(2) Effect on the Elongation Growth of Cryptomeria japonica Branches:

Table 5 given below shows the effect of the treatment with theprohexadione compound on the elongation growth of branches of the 8-yearold young Cryptomeria japonica trees. It will be clear from Table 5 thateven when the agent for inhibiting the formation of Cryptomeria japonicapollen, of the present invention, was used, the elongation growth of theCryptomeria japonica branches was substantially unchanged almost likethat in the control group.

From the above-described facts, it will be clear that although the agentfor inhibiting the formation of Cryptomeria japonica pollen, of thepresent invention, specifically and remarkably inhibits thedifferentiation and formation of male flower buds, the agent exertssubstantially no influence on the elongation growth of the Cryptomeriajaponica branches. TABLE 4 Effect of the agent for inhibiting theformation of Cryptomeria japonica pollen, of the present invention, onthe differentiation and formation of male flowers of 8-year old youngCryptomeria japonica trees Concentration of the Number of undilutedproduct (ppm) male flower clusters Control group 136.9 ± 21.6 0.5 111.6± 25.2 5  70.4 ± 12.4 50 21.2 ± 6.5 500 10.8 ± 6.1

TABLE 5 Effect of the agent for inhibiting the formation of Cryptomeriajaponica pollen, of the present invention, on the elongation growth ofbranches of 8-year young Cryptomeria japonica trees Concentration of theundiluted product (ppm) Branches Elongation (cm) Control group 24.6 ±6.4 0.5 25.5 ± 7.2 5 26.2 ± 6.5 50 24.3 ± 6.3 500 25.2 ± 5.5

EXAMPLE 2

Effect of the Aerial Application of the Agent for Inhibiting theFormation of Cryptomeria japonica Pollen, of the Present Invention, onthe 43-Year Old Cryptomeria japonica Trees

The effect of the agent for inhibiting the formation of Cryptomeriajaponica pollen, of the present invention, applied with a helicopter wasexamined for the purpose of realizing the practical use thereof.

(Materials and Method)

A Cryptomeria japonica forest having 43-year old Cryptomeria japonicatrees (height: 16 m, diameter at breast height: 35 cm) was treated inNirayama experimental plantation of the department of agriculture ofTottori University on Jun. 25, 2001.

The agent for inhibiting the formation of Cryptomeria japonica pollen,thus used had a composition shown in Table 6 given below. Theconcentration of the agent for inhibiting the formation of Cryptomeriajaponica pollen thus sprayed was 50 or 500 ppm. TABLE 6 Composition andconcentration of the agent for inhibiting the formation of Cryptomeriajaponica pollen Agent for inhibiting the Concentration (ppm) formationof Cryptomeria japonica pollen 50 500 Composition Amount (mass %)undiluted product used in Example 1 0.005 0.05 polyoxyethylene castoroil 0.0175 0.175 tetrahydrofurfuryl alcohol 0.0272 0.275 water 99.9599.5

1.8 liters of each of the above described two compositions was appliedto the forest having an area of 10 a by the curtain application methodwith a helicopter. The aerial application was conducted twice, using 0.9liter of the composition each time. In a control group, only water freefrom the active ingredients was used for the aerial application.

Results

(1) Effect on the Differentiation and Formation of Male Cryptomeriajaponica Flowers

Table 7 given below shows the effects of the agent for inhibiting theformation of Cryptomeria japonica pollen on the differentiation andformation of male Cryptomeria japonica flowers of 43-year oldCryptomeria japonica trees.

It will be clear from Table 7 that an excellent effect of inhibiting thedifferentiation and formation of the male Cryptomeria japonica flowerswas confirmed after the treatment with the agent for inhibiting theformation of Cryptomeria japonica pollen, of the present invention,while the serious differentiation and formation of the male flowers wereobserved in the control group. Particularly when the concentration ofthe agent was 50 ppm or 500 ppm, the remarkable effect of inhibiting thedifferentiation and formation of the male flowers was obtained Fromthose results, it is apparent that the differentiation and formation ofthe male Cryptomeria japonica flowers can be remarkably inhibited by theaerial application of the agent for inhibiting Cryptomeria japonicapollen formation, of the present invention, with a helicopter.

(2) Effect on Elongation Growth of Terminal Bud of Cryptomeria japonica

Table 8 given below shows the effect of the agent for inhibitingCryptomeria japonica pollen formation on the elongation growth of 43year-old Cryptomeria japonica trees.

Even when the agent for inhibiting Cryptomeria japonica pollenformation, of the present invention, was sprayed, the elongation growthof the Cryptomeria japonica trees in old stage was substantially thesame as that in the control group. It is thus clear that the agentexerts substantially no influence on the elongation growth.

Thus, when the agent for inhibiting Cryptomeria japonica pollenformation, of the present invention, is used according to the aerialapplication with a helicopter, the differentiation and formation of budsof male Cryptomeria japonica flowers can be remarkably inhibited withoutsubstantially exerting no effect on the elongation growth of theCryptomeria japonica trees. TABLE 7 Effect of the agent for inhibitingthe formation of Cryptomeria japonica pollen, of the present invention,on the differentiation and formation of male flowers of 43-year oldCryptomeria japonica trees in the field Concentration of the Number ofundiluted product (ppm) male flower clusters Control group 2985.8 ±789.1  50  751.3 ± 121.5 500 124.2 ± 55.2

TABLE 8 Effect of the agent for inhibiting the formation of Cryptomeriajaponica pollen, of the present invention, on the shoot elongationgrowth of 43-year old Cryptomeria japonica trees in the fieldConcentration of the technical product (ppm) Shoot Elongation (cm)Control group 80.8 ± 9.4   50 83.3 ± 10.7 500 82.8 ± 11.2

EXAMPLE 3

Effect of Prohexadione Compound Having the Following Chemical Structureon 7-Year Old Young Cryptomeria japonica Trees

(Materials and Method)

Two 7-year old young Cryptomeria japonica trees height: 7.5 m, diameterat breast height: 5.4 cm) which were in a nursery of an experimentalplantation of the department of agriculture of Tottori University andwhich had differentiated and formed male flowers every year were used.Three branches were selected at male flower-forming positions of eachtree. These branches (50 cm long area from the branch top) which weresupposed to form the male flowers were treated with the prohexadionecompound on Jun. 3, 2000 (about one month before the beginning of Julywhen Cryptomeria japonica flowers were supposed to be formed). In thistest, the undiluted prohexadione compound of the present invention shownin Table 9 given below was diluted with 60% (v/v) aqueous acetonesolution to an intended concentration. 100 ml of the diluted solution ofthe prohexadione compound was sprayed on leaves of the branches with ahand sprayer. In a control group, the leaves were treated with only 60%(v/v) aqueous acetone solution.

Concentrations of the undiluted product used for the foliar spraytreatment:

Concentration (ppm)

-   -   5    -   50    -   500        Results

Table 10 shows the effect of the agent for inhibiting Cryptomeriajaponica pollen formation, of the present invention, on thedifferentiation and formation of male flowers of 7-year old youngCryptomeria japonica trees. It is clear from Table 10 that the excellenteffect of inhibiting the differentiation and formation of the maleCryptomeria japonica flowers was confirmed after the treatment with theagent for inhibiting the formation of Cryptomeria japonica pollen, ofthe present invention, while the serious differentiation and formationof the male flowers were observed in the control group. Particularlywhen the concentration of the agent was 50 ppm or 500 ppm, theremarkable effect of inhibiting the differentiation and formation of themale Cryptomeria japonica flowers was obtained.

Table 11 shows the effect obtained by the treatment with the agent forinhibiting Cryptomeria japonica pollen formation, of the presentinvention, on the elongation growth of the branches of the 7-year oldyoung Cryptomeria japonica trees. It is clear from Table 11 that evenwhen the agent for inhibiting Cryptomeria japonica pollen formation, ofthe present invention, was used for the treatment, no effect wasobserved on the elongation growth of the Cryptomeria japonica branchesas in the control group.

It is thus clear that the agent for inhibiting the formation ofCryptomeria japonica pollen, of the present invention, is excellent ininhibiting the male flower formation and it exerts substantially noinfluence on the elongation growth of the Cryptomeria japonica trees.TABLE 10 Effect of the agent for inhibiting the formation of Cryptomeriajaponica pollen, of the present invention, on the differentiation andformation of male flowers of 7-year old young Cryptomeria japonica treesConcentration of the Number of formed male undiluted product (ppm)flowers (clusters) Control group 107.6 ± 18.9 5  75.1 ± 15.2 50 29.3 ±8.2 500  7.8 ± 3.5

TABLE 11 Effect of the agent for inhibiting the formation of Cryptomeriajaponica pollen, of the present invention, on the shoot elongationgrowth of branches of 7-year old young Cryptomeria japonica treesConcentration of the undiluted product (ppm) Shoot Elongation (cm)Control group 23.5 ± 3.4 5 21.5 ± 4.9 50 22.2 ± 7.7 500 23.2 ± 5.1

According to the present invention, the agent for inhibiting theformation of Cryptomeria japonica pollen effective in inhibiting theformation of the male flowers without substantially inhibiting theelongation growth of the Cryptomeria japonica trees can be obtained.

1. A method for inhibiting the formation of Coniferophyta pollen, whichcomprises applying a pollinosis inhibiting effective amount of acomposition comprising a prohexadione compound as an active ingredientto the Coniferophyta plant to be treated.
 2. The method according toclaim 1, wherein said prohexadione compound is acyclohexanedionecarboxylic acid derivative of the following formula (AI)or a salt thereof:

wherein A represents —OR₂ or —NR₃R₄, B represents a hydroxyl group, and—NHOR₁ group or a metal salt or ammonium salt thereof, R represents analkyl group having 1 to 6 carbon atoms or a cycloalkyl group having 3 to6 carbon atoms, R₁ represents an alkyl group having 1 to 6 carbon atoms,a haloalkyl group having 1 to 6 carbon atoms, an alkenyl group having 3to 6 carbon atoms, a haloalkenyl group having 3 to 6 carbon atoms or analkynyl group having 3 to 6 carbon atoms, and R₂, R₃ and R₄independently represent a hydrogen atom, an alkyl group having 1 to 6carbon atoms, a haloalkyl group having 1 to 6 carbon atoms, analkoxyalkyl group having 2 to 10 carbon atoms, an alkylthioalkyl grouphaving 2 to 10 carbon atoms, an alkenyl group having 3 go 6 carbonatoms, an alkynyl group having 5 or 6 carbon atoms, or a phenyl group oran aralkyl group having 1 to 6 carbons, and R₃ and R₄ may form a 5- or6-membered heterocyclic ring together with the carbon atom to which theyare bonded and the ring may further-contain a carbon atom or sulfuratom.
 3. The method according to claim 2, wherein A in the formula (AI)represents an —OR₂ group.
 4. The method according to claim 2, wherein Ain the formula (AI) represents an —NR₃R₄ group.
 5. The method accordingto claim 2, wherein R in the formula (AI) represents a cycloalkyl grouphaving 3 to 6 carbon atoms.
 6. The method according to claim 2, whereinsaid prohexadione compound is represented by the following formula AIa:


7. The method according to claim 1, wherein said prohexadione compoundis represented by the following formula BI:

wherein R represents a hydrogen atom or an alkyl group, and R¹represents an alkyl group.
 8. The method according to claim 1, whereinsaid prohexadione compound is represented by the following formula (CI):

wherein R¹ represents a hydrogen atom or a lower alkyl group, R²represents a lower alkyl group, R³ represents a hydrogen atom, an alkylgroup, an alkenyl group, a hydroxyalkyl group, a cycloalkyl group,morpholino group, an aminoalkyl group, an N-alkylaminoalkyl group, anN,N-dialkylaminoalkyl group, an alkoxycarbonylalkyl group, a group ofthe formula:—(CH₂)₁R⁴ (wherein R⁴ represents a lower alkyl group, a lower alkylthiogroup, a benzylthio group, an anilino group, a morpholino group, apiperazino group or a piperidino group, and 1 represents an integer of 2or 3); a group of the formula:

(wherein X represents a halogen atom, a lower alkyl group, a loweralkoxyl group, a phenoxy group or an alkoxycarbonylalkyloxy group, mrepresents an integer of 0 or 1, and n represents an integer of 0 to 2);a group of the formula:—CH₂R⁵ (wherein R⁵ represents a furyl group, a thenyl group or a pyridylgroup), or a group of the formula:

(wherein R⁵ is as defined above).
 9. The method according to claim 1,wherein said prohexadione compound is represented by the followingformula (DI):

wherein R¹ represents a hydrogen atom, a lower alkyl group or a phenylgroup, X represents an oxygen atom or a sulfur atom, R² represents ahydrogen atom, an alkyl group, an alkenyl group, an alkylthioalkylgroup, an alkoxycarbonylmethyl group, a benzyl group substituted with ahalogen atom, a group of the formula:

(wherein Y represents a carbonyl group, a sulfonyl group or a sulfonategroup, Z represents a hydrogen atom, a halogen atom, a lower alkylgroup, a lower alkoxyl group, a cyano group or a trifluoromethyl group,m represents 0 or 1, and n represents an integer of 1 or 2, with theproviso that when n represents 2, Z may be a combination of differentgroups or atoms), a furyl group or a thienyl group.
 10. The methodaccording to claim 1, wherein said Coniferophyta plant is Cryptomeriajaponica.